1. Field of the Invention
The present invention relates to a method for forming phosphor layers of a plasma display panel (PDP), an apparatus for the method, a filament-like article for the method and a method for manufacturing the filament-like article. More particularly, the present invention relates to a method and apparatus for forming the phosphor layers in grooves each defined between ribs (partition walls) on a substrate in a manufacturing process of the plasma display panel.
2. Related Arts
A PDP is a display panel comprising a pair of substrates (typically, glass plates) disposed opposite to each other with a plasma discharge space sandwiched therebetween. When ultraviolet-ray excitation type phosphor layers disposed in the discharge space are excited by ultraviolet rays generated by electric discharge, the PDP displays colors. The PDP has three kinds of phosphor layersxe2x80x94R (red), G (green) and B (blue).
The phosphor layers of R, G and B are each formed using a process in which phosphor pastes containing phosphor powders are sequentially applied between ribs on a substrate by a screen printing method using a screen mask, followed by drying and sintering (for example, see Japanese Unexamined Patent Publication No. Hei 5(1993)-299019).
However, as the size of the PDP becomes larger, the alignment of ribs and mask-patterns becomes more difficult because of the distortion and extension of the masks. Therefore, it is becoming more difficult to apply phosphor pastes precisely among ribs.
The present invention has been made in view of the above circumstances. An object of the present invention is to form the phosphor layers uniformly and precisely among the ribs to form a large-sized PDP by means of a unique technique which places a filament-like article containing a phosphor among ribs.
The present invention provides a method for forming a plurality of stripe-like phosphor layers on a surface of a substrate constituting a plasma display panel, the surface having a plurality of parallel ribs disposed thereon and grooves each defined between two adjacent ribs, comprising the steps of: molding a phosphor paste composed of a phosphor and a first synthetic resin into a filament-like article; placing the molded filament-like article into each groove; filling the grooves with a solvent optionally containing a second synthetic resin compatible with the first synthetic resin; and conducting a sintering treatment of the substrate to form the phosphor layers in the grooves.
The present invention also provides an apparatus for forming a plurality of stripe-like phosphor layers on a surface of a substrate constituting a plasma display panel, the surface having a plurality of parallel ribs disposed thereon and grooves each defined among two adjacent ribs, comprising: a mounting base for mounting the substrate thereon and a supplier for supplying a filament-like article into each groove, the filament-like article being made of a phosphor and a synthetic resin.
The present invention also provides a filament-like article made by mixing a phosphor and a synthetic resin in a solvent, molding the resultant mixture into a filament shape and evaporating the solvent.